Sky Monsters (DVD Review)

No, they weren’t dinosaurs. True, model sets of extinct animals often include saber-tooth cats, sail-backs (which were mammal-like reptiles and more closely related to us than to dinosaurs) and extinct marine reptiles as well as pterosaurs, but none of these are actually dinosaurs. Pterosaurs did, however, live alongside dinosaurs and are of great interest as the largest animals ever to fly on their own.

This DVD, another of the National Geographic series, looks at the mystery of pterosaur flight. As usual, the animation is not very exciting, but the scientific work and the attempt to build a mechanical pterosaur more than makes up for that.

The big questions are, how large did pterosaurs grow and how did they fly?

One of the threads of the program is the rather controversial discoveries of trackways and fossils suggesting even larger pterosaurs than Quetzalcoatlus, which itself had a wingspan of 10 meters (33 feet.) That’s three times larger than an albatross, the largest flying bird alive today. Forget the giants; how did even the ones we’re reasonably sure of fly?

The meat of the DVD, as far as I was concerned, was an attempt to build a robotic pterosaur, controlled like a model airplane. The result was not wholly successful, but a great deal was demonstrated about pterosaurs in the process.

First, pterosaur wings were a good deal more complicated than the sailcloth that was first tried. They had oriented stiffening fibers, muscles within the wing membrane, a good blood supply to the wings, a furry covering that (like the dimples on a golf ball) helped aerodynamically, and some kind of built-in sunscreen. (Bats are nocturnal in part because their wings would sunburn too badly in daylight.)

Control was incredibly sophisticated, certainly more so than could be mimicked by a model airplane controller. Much of the maneuvering of a real pterosaur was probably as automatic as keeping your balance is to you – possibly more so, if the speculation that baby pterosaurs were born knowing how to fly is correct. Changing the shape of the wings and the tilt of the head would have been automatic for a real pterosaur. Not so for the model, and it is hardly surprising that it was not fully successful, even aside from the problems of finding components and power sources of sufficiently light weight. Pterosaurs, like birds, had very light bone structures.

As entertainment this DVD falls short. But as documentation of a fascinating experiment, it is worth watching.

Alaskan Mesozoic 3

One of the problems faced by teachers at any level is questions.

Very young children are full of questions – the problem is keeping a class from disintegrating into chaos. Somehow parents, school and adults in general manage to turn that questioning off, at least in the classroom. In teaching college courses, I found that it was very difficult to get students to ask any questions. And a good teacher relies on student questions, if only to provide feedback on whether he or she has gotten the point across.

I recall a math class at Harvard where the professor was totally stunned by the abysmal results of the first test. Most of us hadn’t had the least idea of what he was talking about, but were so confused we didn’t even know what to ask. If some of us had just spoken up and said “I don’t understand that,” he might have realized what we only understood in retrospect – he had not bothered to find out exactly what the preceding class had covered, and a large and essential chunk of the necessary background to what he was teaching had never been covered. In this case, I think we were all afraid of looking stupid in the eyes of the other students.

I’m not talking about huge lecture classes, of course. But in smaller groups, often with a graduate assistant, questions do need to be asked – and frequently are not. As a result, those who teach in college settings generally plan their lectures assuming there will not be many questions.

Many of our local OLLI classes, for adults over 50, are taught by college professors, often retired. These lecturers plan their courses as if we were college students, with a typical student’s reluctance to ask meaningful questions. It doesn’t work, at least not in Fairbanks. We older students are full of questions, especially when our instructors are active researchers of what they are teaching.

The final lecture of “The Mesozoic of Alaska” was supposed to cover marine reptiles and pterosaurs. Well, the marine reptile – an ichthyosaur discovered on the North Slope – was indeed covered, in the last five minutes of the two-hour class. I had to ask about the pterosaurs after class.

I think that Pat (who is not retired) intended to give a brief overview of what kinds of dinosaur fossils have been found in Alaska, followed by the story of the excavation of the ichthyosaur (which turned out to have co-discovered by Carl Benson, one of my dissertation advisors) and the trace fossils of pterosaurs. He passed around casts of fossils of numerous types of dinosaurs found along the Colville River, told stories of floating the Colville hunting for dinosaur bones in the thawing banks, and showed artists’ conceptions of the living beasts. And he had to field tons of questions.

I won’t go into the classifications of Saurischia and Ornithischia, you can look at Wikipedia if you’re interested. Here in Alaska, we had Edmontosaurus (a duck-bill) chowing down on the vegetation, accompanied (not always on the Colville) by ankylosaurs,  Thescelosaurus, hadrosaurs and Pachyrhinosaurus. They were eaten by large and small two-legged predatory dinosaurs: big-eyed Troodons, the Tryannosaurid Albertosaurus, and another small, pack-hunting killer, Sauromitholestes.

The pterosaurs? They were here, as shown by a trace fossil of the “hand” of one. Their bones are so delicate that it is no surprise fossils have not been found yet in Alaska, but they were here. At least there is no problem with their possible migration, which is still hotly debated for the land-dwelling dinosaurs.

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